Heat control



I. A914128, 1942- J. W. wAT-rLEsV-D 2,281,399

HEAT CONTRO L Fileq Jan. 7, 1959 HIGH HEAT UNIT-H LOW HEAT UNIT ,H

HEAT To BUILDING SQ ./TS

Patented 28, 1942 signor to `MinneapolsHoneywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Appuati'n January 7, 1939, seria1N0.2-49,79z

' geminis. (crass-ss) This invention relates to heat control systems of the'type which employ a casing having radiai tion cha.ra'cteristicsl similar to those -oi' the building to be heated and being located outside the building where it is'exposed to similar weather j conditions,V the casing containing thermostatic means for controlling the supply of heat both to the building and also to the casing. The usual sourcesof heat supply comprise a steam Aplant for the building and electric heatingunits for the casing, thesteam plant usually being located outside the building and the heating coils being disposed'within the casing. Bysupplying heatvto p the casing andbuilding respectively at rates sumcient to keep them at approximately' equal tem- 'l peratures when they are in normal condition and controlling both supplies in response toy the temperaturer within thecasing, many advantages are obtained;v For example, if tenants'in an apartment house waste heat by opening windows toov Y much, the Waste resultsl merely in a temperature drop in the apartment; the amountl of heat I supplied, to the building remains unaffected because the heat supply is responsive o'nly. to the temperature in the outside casing.

Objects of the present invention are to provide vide quicker and more accurate temperature cono trol and which are generally superior to the control systems of the prior art.

With prior control systems of the aforesaidtype it has been possible to regulate thev temperature oi the building only by varyingthe frequency aridi-length of the perods'during whichj heat issu'pplied, not by changing the'rate of supply` duringany period or during successive which heat.

varied,k either; lwith ori without thel otherv variations. Thi'sis accomplished by supplying'vheat to the casing at different rates proportional lto the rates-atgwhich, heat issupplied [tothe building, depending upon the outdoor temperature,- the "rate preferably changing by substantial steps .ratherl than gradually. The proportional variations in` thevheat supplied to the casing and building are controlled by thermostatic-means -responsive to the 'temperature withinthe casing. By changing the heat supply in steps' rather than gradually the apparatus may be greatly simplified. For example, the apparatus in the outside casing may comprise merely one or more thermostats and one or moreheaters for supplying heat to the casing at dierent rates and the apparatus in the building need comprise only a well-known control systems of the aforesaid typev which protype of steam valve having a plurality of solenoids for opening the valves dierent degrees respectively.

For the purpose of illustration a typical embodiment of the invention is shown in the 'ac- A companying drawing in which the gure is a dagrammatic representation o1 a system of the aforesaid type adapted to supply` heat to a building at two diierent rates.

'The particular embodiment of the invention.

chosen for the purpose -ofV illustration comprises a valve V for regulating the ilow of steam through a pipe P to the radiators of abuilding which are not shown. Inasmu'ch as solenoid` valves ofthis type are well-known the valve is shown diagram-` matically, S and S' representing the solenoidsof the valve. The aforesaid casing-'ifs indicated by,` the broken line C, a suitable' construction being,y

shown in detail in my prior Patent 2,065,844 granted December 29, 1936. Located i'n the casing C are two thermostats T 'and T', and two heating coils H and H'. These four devices are interconnected with the apparatus for control-` ling the'valve V through four conductors I, 2, 3

and 4. As indicated by the broken 4portions of the conductors all the apparatus other than,l that located in the casing C is placed at a remote location, preferably in a suitable control cabinet in the building to be-heated. In the illustrated embodiment this control apparatus comprises two relays R. and R', a time switch TS, a night thermostat NT, a resistance 5 in the conductor 4, a rheostat 6 connected .to the conductor 3, a

` pilot light 1, manual'switchs 8, 9 and I0 and is, suppuea to the binding may' be Y conductors Il to 24 inclusive. i

kSolenoid Seis supplied WithcuTrent-through a circuit ill-I2 which is controlled by the relay i R and the manual switch- BrzWhen the switch 8 4 is closed thecircuit is under"the control oi" the relay R and Whenthe switch isfopen the circuit is inoperative." The solenoid 'S' is controlled by relay R' 'through the circuit lS-IL As indi'- -cated` in the drawing the solenoid circuits are supplied with' current froml suitable' sources through the conductors iB-i and H -IB respectively. All the other circuits -are supplied with current through the conductors IS--ZtL- The relay R is controlled by the thermostat T over the following circuit: conductor 20, either the night switch NT or the time switch TS, conductor 22, relay R, resistance 5, conductor l, thermostat T, heating unit H, conductor 3, rlieostat 6, conductor 23 and conductor I9 back tor the other side of the source of current. The relay R' is controlled by the thermostat T' over the following circuit: conductor 20, night thermostat NT or time switch TS, conductor I, thermostat T', conductor 2, switch I0, switch 9, relay R', conductor 24 and conductor i9 back to the other side of the source of current. Inasmuch as the pilot I is in parallel with the relay R' it is of course always lighted when the relay is energized. When the thermostat T closes the circuit of relay R it also closes the following circuit for the heater H: conductor 20, night thermostat NT or time switch TS, conductor I, thermostat T', heater H', conductor 3, rheostat S, conductor 23 and conductor I9 back to the other side of the source of current. Thus when the relay R is energized to operate the solenoid S the heater H is also energized, in series with the relay; and when the relay R' is energized to operate the solenoid S' the heater H is also energized, in parallel with the relay.

The time switch TS may be adjusted to close the circuit at `recurrent intervals of any desired length and frequency, such as five minutes out of every fifteen-minute interval. The night thermostat NT may be set to close at any desired temperature, such as 60". The time switch TS is preferably arranged to close circuit only during the day time, whereby no heat can be supplied to the building during the night time until the ternperature of the building drops to the point to which the night thermostat NT is set. Obviously the present invention may be utilized with only one or the other of the devices NT and TS or with neither of these devices. If neither device is employed the conductor 20 would of course be permanently connected to the conductor I. By opening the switch 8 the solenoid S is rendered inoperative and by opening the switch 9 the solenoid S' is rendered inoperative. By shifting the switch I0 to the-contact M the relay R' may be manually controlled by switch 9 through the circuit: conductor 20, switch contact M, switch I0, switch 9, relay R', conductor 24 and conductor I9 back to the other side of the source of current. During this manual control the thermostats T and T continue to control the heaters H and H' so that the casing C is ready for automatic operation when switch Ill is shifted back to automatic operation.

As indicated in the drawing the solenoids S and S' may be arranged to 'supply heat to the build! ing at low and high rates respectively. For example, the solenoid S may admit steam at a pressure of 8 ounces and the solenoid S' may admit steam at a pressure of 3 pounds. The heaters H `and 'H' in thecasing C are correspondinglyV ad justetl, the heater H supplying a small amount of heat to the casing C and the heater H supplying' a large amount of heat to the casing `C.- The thermostats-T 4andlT' maybe adiusted to close at any desired high and low temperatures respectively. For example, thethermostat T may operate at '66-68 E. and' th'e thermostat T "may operate at 64-66 From the foregoing 'it will be understood that when the temperature in the casing C drops to say 66 the thermostat T closes to energize the low-heat unit H and the low-heat solenoid S, the unit H heating the interior of the casing at s"^h a rate as to open the thermostat T when the building has reached the desired temperature. 1n case of a drop in the outdoor temperature or in case the outdoor temperature is very low the temperature inside the casing C may drop to the point where the thermostat T' closes, thereby energizing the high-heat unit H' and the high-heat solenoid S' to supply heat to the casing and building at a more rapid rate. The heater H' is so adjusted that when the temperature in the building has risen almost to the desired level the temperature inside the casing C has risen to the point where the thermostat T' opens, thereby reducing the supply of heat to both casing and building to the lower rate. vIf the temperature rises to the point where even the low-rate heat is not required, thermostat T also opens wholly to discontinue the supply of heat to both casing and building.

It'should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modications and equivalents which fall within the scope of the appended claims.

I claim:

l. A system for controlling the supply of heat exchange to a zone at high or low rates comprising a casing having radiation characteristics similar to those of the zone for exposure to similar weather yconditions outside the zone, control switches'for regulating said heat supply at high and low rates respectively, electrical actuating means for operating the control switches, two thermostats in said casing, two heaters in said casing, and an energizing circuit for each of said electrical actuating means including in series switch means operated by one of said thermostats, one of said casing heaters, and one of said electrical actuating means, the casing heater in the energizing circuit for the electrical actuating means for the high rate control switch supplying heat to the casing at a higher rate than the other casing heater.

2. A system for controlling the supply of heat exchange to a zone at high or low rates comprising a casing having radiation characteristics similar to those of the zone for exposure to similar weather conditions outside the zone, means for regulating said heat supply at high and low rates respectively, high rate and low rate heaters in said casing for supplying heat to the casing 

